In die casting operations for non-ferrous metals, such as aluminum, zinc, magnesium, copper, tin, lead and their alloys, the dies or molds are coated with a release agent. Aqueous emulsions have been used in the past which leave a wet, oily film on the die. The oily appearance of the film makes it difficult to detect dryness and the degree of die coverage. A dry, adequately coated die surface is required because the presence of water vapor in the die cavity can cause the castings to be porous, and over or under coverage of the die surface causes checking of the dies or sticking of the castings respectively. These emulsion products also produce some smoke. I have now discovered aqueous release agents which provide a dry, easily-detected, visible white film on the die, produce no smoke, and which result in improved quality castings.